The invention relates to contactless communication between a portable object and a terminal.
Contactless data interchange is well known; applications of this technique include, in non-limiting manner, controlling access and remote payment, e.g. for access to and payment for public transport.
In this example, each user is provided with a portable object of the xe2x80x9ccontactless cardxe2x80x9d or xe2x80x9ccontactless badgexe2x80x9d type, which object is capable of interchanging information with a fixed terminal or station by moving the portable object close thereto so as to enable mutual non-mechanical coupling to take place therebetween (the term xe2x80x9cterminalxe2x80x9d is used herein to designate a data transceiver terminal suitable for co-operating with portable objects).
The invention relates to the particular situation in which a plurality of portable objects can be present simultaneously in the field of action of the terminal, and where there are no physical means, e.g. insertion into a slot, for isolating the arrival of a single object only in said field.